Composting 101: Humus Happens

Healthy garden soil is a living system that forms the backbone of a healthy garden – and compost is a superfood that feeds that system. It’s a cost-free way to introduce beneficial organisms and add nutrients your plants crave, all while diverting waste from landfills. There are a few guidelines to follow when it comes to creating a healthy compost pile, and getting the recipe right will brew up a healthy soil amendment that can be added throughout the season.

What’s compost?Compost is a mixture of decomposed vegetation. Tiny beneficial organisms help the decomposition process by eating and digesting plant material, and they eventually break down all plant byproducts to create humus, one of the main ingredients of finished compost. Making compost is a lot like baking bread: In breadmaking, once the alchemy of water, yeast, flour and fermentation have taken place, you just need to bake it. In composting, microbes do most of the work for you, feasting on and digesting rotten plant materials to transform them to humus and create a new compost base.

Brown vs. greenTo build a healthy, active compost pile, you’ll need two different categories of ingredients: browns and greens. Browns – usually dried-out parts, newspaper, dried grass, straw or wood chips – bulk up your compost bin, acting as a source of carbohydrates for the microorganisms that break down plant material. If it’s dried out, you can probably consider it a brown.Greens – the fruit and vegetable scraps, grass clippings and garden cuttings – are a source of nitrogen or protein, which the microorganisms consume as energy for growth and strength. During decomposition, greens are what heat up your pile. The organisms that feed on the decomposing material generate the heat, which aids in the breakdown of plant material.

What ratio of green to brown is right? The general rule of thumb is two parts brown to one part green. More active gardeners or people who generate a lot of kitchen scraps can sometimes get a 1:1 ratio of browns vs. greens. The more frequently you add to your pile, the lower the ratio you can get away with.

No-no’s for compostingAs home gardeners, we don’t want to attract animals looking for food. Contrary to popular belief, it’s easy to avoid if you keep a few items out of your compost. Don’t add animal-based materials like bones, meat, fatty waste or animal-based soup stock. Also avoid throwing in dairy products like cheese and milk, which will get rancid in your compost.

Watering and turningAfter your initial layers have been placed in the container of your choice, you’ll need time and water. Your compost pile is alive just like your soil, and will need moisture along with food to fully decompose – but just keep it damp, not soggy. When the compost pile sinks to about a third of its original size, it will need to be turned. This pushes new material into the center and allows your hard-working microorganisms access to more food, while spreading already decomposed material to the outside (you’re essentially stoking the fire to speed things up). After two to three turns of your compost pile, you’ll likely have a finished product that’s ready to be used on plants.

When is it ready?Decomposition time depends on how well your compost pile is maintained and what season you’re in. During hot summer months, you can have a finished cycle of compost in as little as three weeks. In the fall, when microbes are slowing down and going dormant, it may take much longer. Rest assured, if it looks like soil and smells like soil, your compost is complete and ready to become the healthy boost your garden needs.